The present invention relates to an improvement in a welding head for narrow gap welding with a contact nozzle for a welding electrode, the contact nozzle being laterally pivotal by operating means with respect to the longitudinal extent of the gap, about a shaft disposed in a nozzle holder.
It is known, in multi-pass welding of relatively narrow and deep gaps between two workpiece parts, to use a filler wire holder which is pivotal about an axis located outside the gap in such a manner that the gap can be filled with two or more welding passes beside and overlapping one another.
For welding together two substantially cylindrical workpiece parts along a narrow gap in a plane substantially at right angles to the axis of the cylinder, it is also known to utilize an elongate filler wire holder which extends into the gap substantially perpendicular to the direction of feed of the filler wire. The filler wire holder is, here, arranged for pivoting on its own longitudinal axis in that it is mounted in pivot bearings located outside the gap.
This latter welding apparatus allows for a relatively large angular movement of the filler wire between the two extreme positions on one and the other side of the gap. The thus obtained, relatively great inclination of the filler wire has resulted in an improved welding quality; this in comparison with the quality of welding using a smaller filler wire inclination. One disadvantage inherent, however, in this apparatus is that the filler wire holder, because of its length, is not capable of holding the filler wire with sufficient stability, for which reason it is not possible to direct the path of travel of the filler wire as accurately as might be desired.